Sattellite Radio Option?

My 2004 545i has most options (navigation, integrated phone and in-dash 6 disk changer). There are connectors, wiring and a bracket in the trunk that appear to be for a sattelite receiver. However, since the build sheet does not include the sattellite radio prep option. my BMW dealer says there is no way to install a factory receiver. Does anyone have any ideas on how to proceed to install a factory or near-factory package?